1. Field of the Invention
The invention is directed to an improved high-pressure connection device for delivering fluid such as fuel to a device, for example a fuel injector.
2. Description of the Prior Art
One high-pressure connection device, known from Published, Nonexamined German Patent Application DE 197 53 518 A1, for instance, serves to deliver a fluid, preferably fuel, to an apparatus. Such a high-pressure connection device has a housing in which a receiving opening is embodied. Discharging into this receiving opening is an inlet conduit, which extends in the housing and through which the fluid can be conducted at high pressure. The high-pressure connection device furthermore contains a pressure tube connector stub with a high-pressure conduit embodied in it, through which the fluid can likewise be conducted at high pressure. The high-pressure conduit discharges at an end face of the pressure tube connector stub and communicates sealingly with the inlet conduit extending in the housing once the pressure tube connector stub is screwed, with a male thread embodied on it, into a female thread embodied in the receiving opening. The pressure tube connector stub, on its end face, has a sealing face, which when the pressure tube connector stub is screwed in is tensed against a seat face embodied in the receiving opening, so that the inlet conduit in the housing is made to communicate sealingly with the high-pressure conduit in the pressure tube connector stub.
The male thread on the pressure tube connector stub and the female thread in the receiving opening of the housing are typically embodied as 60° standard threads. This means that both flanks of the thread courses form an angle of at least approximately 60° with the longitudinal axis of the thread, so that between the two thread flanks as well, an angle of 60° is enclosed. If external or other factors result in a lateral force on the pressure tube connector stub, then the thread flanks of the female thread and the male thread become slightly shifted from one another. As a result, the pressure tube connector stub is somewhat skewed from its original axis, because the lateral flanks of the male thread on the pressure tube connector stub that receive the tensing force slide along the thread flanks of the female thread and thus also deviate in the axial direction. Since the sealing face of the pressure tube connector stub surrounds the orifice of the high-pressure conduit, the pressure per unit of surface area of the sealing face on the seat face decreases on the side where the lateral force engages the pressure tube connector stub. This can create leaks, since a more or less high pressure prevails in the high-pressure conduit and in the inlet conduit.